1. Field of the Invention
The present invention relates generally to adjustable axles on agricultural equipment such has self-propelled sprayers, and, more specifically, to a shim structure for maintaining a tight fit on a telescoping axle.
2. Related Art
Self-propelled agricultural vehicles often require structure to adjust wheel spacing. To accommodate different row spacings in row crop applications, for example, the wheel spacing on a sprayer may have to be changed numerous times over a season as the vehicle operates in different fields. Various types of axle telescoping structure with shimming arrangements are available to adjust tread, but most suffer from one or more disadvantages. A typical telescoping axle structure utilizes inner and outer tubes of generally square cross section. During initial assembly of the axle structure, shim plates are added between the tubes, and the number of plates varies with the tolerance of the inner and outer tubes of the telescoping assembly. Therefore the number of plates must be chosen carefully, and often all four sides of the tubes must be shimmed for a snug fit. If additional shim plates later become necessary after the assembly loosens as a result of wear and tear, the axle must be disassembled to add the plates. Providing a quick, simple, and effective means of shimming an adjustable axle with telescoping tubes of square section, both during initial assembly and later repair or refurbishing, and maintaining snug fit over the life of the machine, have been continuing problems.